Replace hyperlinks in a textual pattern.

gistfile1.php

<?php
$description = htmlspecialchars($description);

$matches = array();
preg_match_all('/(\w+:\/\/)?([-\w@:]+\.)+[-\w@:]+(\/\S*)?[^)"\'»”’!?.\s]/', $description, $matches, PREG_SET_ORDER);
$startPos = 0;
foreach ($matches as $match) {
    $pattern = $match[0];
    if (!isset($match[1]) || !$match[1]) {
        $pattern = "http://{$pattern}";
    }
    $replace = '<a href="' . $pattern . '">' . $pattern . '</a>';

    // Find the position of the match so that we replace it and ONLY it.
    $i = 0;
    do {
        $pos = strpos($description, $match[0], $i);
        ++$i;
    } while ($pos < $startPos);

    $tempDescription = substr($description, $pos);
    $tempDescription = preg_replace('$' . preg_quote($match[0], '$') . '$', $replace, $tempDescription, 1);
    $description = substr($description, 0, $pos) . $tempDescription;
    $startPos = $pos + strlen($replace);
}

$description = str_replace("\n", "<br />", $description);
return $description;